Extending EPON Multi-Point Control Protocol to Run on Ethernet PON over Coax Networks

ABSTRACT

A method implemented by a middlebox comprising registering a customer premises equipment (CPE) in the middlebox, wherein the CPE is coupled to the middlebox via an electrical line, and facilitating registration of the CPE in a central office (CO) equipment coupled to the middlebox.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 14/673,461 filed Mar. 30, 2015 by Futurewei Technologies, Inc.and titled “Extending EPON Multi-Point Control Protocol to Run onEthernet PON over Coax Networks,” which is a continuation application ofU.S. patent application Ser. No. 13/789,318 filed Mar. 7, 2013 byFuturewei Technologies, Inc. and titled “Extending EPON Multi-PointControl Protocol to Run on Ethernet PON Over Coax Networks,” whichclaims priority to U.S. provisional patent application No. 61/607,734filed Mar. 7, 2012 by Liming Fang, et al., and titled “Method andApparatus of Extending EPON MPCP to Run on Ethernet PON Over CoaxNetwork (EPoC),” which are incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

A passive optical network (PON) is a system for providing network accessover “the last mile.” In a downstream direction, the PON may be apoint-to-multi-point (P2MP) network comprising an optical line terminal(OLT) at a central office, an optical distribution network (ODN), and aplurality of optical network units (ONUs) at customer premises. Ethernetpassive optical network (EPON) is a PON standard developed by theInstitute of Electrical and Electronics Engineers (IEEE) and specifiedin IEEE 802.3ah, which is incorporated herein by reference as ifreproduced in its entirety. EPON may provide a simple and flexible wayof using optical fiber for broadband service in the last mile.

In EPON, an optical fiber may be used for both upstream and downstreamtransmissions with different wavelengths. The optical line terminal(OLT) may implement an EPON media access control (MAC) layer fortransmission of Ethernet frames. A multi-point control protocol (MPCP)may perform various services such as bandwidth assignment, bandwidthpolling, auto-discovery, and ranging. Ethernet frames may be broadcasteddownstream based on a logical link identifier (LLID) embedded in apreamble of each frame. On the other hand, upstream bandwidth may beassigned based on the exchange of Gate and Report messages betweenmessages between an OLT and an ONU.

Recently, hybrid access networks employing both EPON and other networktypes have attracted growing attention. For example, Ethernet over Coax(EoC) may be a generic name used to describe all technologies thattransmit Ethernet frames over a unified optical-coaxial (coax) network.Examples of EoC technologies may include EPON over coax (EPoC), dataover cable service interface specification (DOCSIS), multimedia overcoax alliance (MoCA), G.hn (a common name for a home network technologyfamily of standards developed under the International TelecommunicationUnion (ITU) and promoted by the HomeGrid Forum), home phonelinenetworking alliance (HPNA), and home plug audio/visual (A/V). EoCtechnologies may have been adapted to run outdoor coax access from anONU to an EoC head end with connected customer premises equipment (CPEs)located in subscriber homes.

There is a rising demand to use EPON as an access system to interconnectwith multiple coax cables to terminate coax network units (CNUs) locatedin a subscriber's home with an EPoC architecture. In an EPoC system, asa physical (PHY) layer in the optical network portion may be relativelycleaner than a physical layer in the coax network portion, one may needto establish channel communication between CNUs and OLT beforetransmission of data. Some traditional discovery and registrationapproaches may use EPON MPCP for registration of coaxial line terminals(CLTs). However, traditional MPCP may not be used for the coax networkportion. Thus, it is desirable to extend the EPON MPCP to the coaxportion of an EPoC network, where noises may be higher.

SUMMARY

In one embodiment, the disclosure includes a method implemented by amiddlebox comprising registering a customer premises equipment (CPE) inthe middlebox, wherein the CPE is coupled to the middlebox via anelectrical line, and facilitating registration of the CPE in a centraloffice (CO) equipment coupled to the middlebox.

In another embodiment, the disclosure includes an apparatus comprising aprocessor configured to register a customer premises equipment (CPE)remotely coupled to the apparatus via an electrical line, and facilitateregistration of the CPE in a central office (CO) equipment coupled tothe apparatus.

In yet another embodiment, the disclosure includes a method comprisingreceiving a first discovery message from a middlebox coupled to acustomer premises equipment (CPE) via an electrical line, transmitting afirst register request message to the middlebox in response to the firstdiscovery message, receiving a first register message from themiddlebox, wherein the first register message comprises a physical layeridentifier (PHY ID) for the CPE; and receiving a second discoverymessage from the middlebox, wherein the second discovery messagecomprises an identifier (ID) for a central office (CO) equipment coupledto the middlebox.

These and other features will be more clearly understood from thefollowing detailed description taken in conjunction with theaccompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1 illustrates an embodiment of an EPoC network.

FIG. 2 illustrates an embodiment of a DOCSIS network.

FIG. 3 illustrates an embodiment of a hybrid access network.

FIG. 4 illustrates an embodiment of part of a layer architecture in ahybrid access network.

FIG. 5 illustrates an embodiment of a registration protocol.

FIGS. 6A and 6B illustrate an embodiment of a registration method.

FIG. 7 illustrates an embodiment of a network node.

DETAILED DESCRIPTION

It should be understood at the outset that, although an illustrativeimplementation of one or more embodiments are provided below, thedisclosed systems and/or methods may be implemented using any number oftechniques, whether currently known or in existence. The disclosureshould in no way be limited to the illustrative implementations,drawings, and techniques illustrated below, including the exemplarydesigns and implementations illustrated and described herein, but may bemodified within the scope of the appended claims along with their fullscope of equivalents.

Based on needs at any time (in other words, on demand), a customer mayswitch a CNU off and on as desired. The non-contention based design ofEPON as well as EPoC MAC layer may be such that ONUs/CNUs do nottransmit data upstream until they have been allocated a timeslot througha GATE message. Hence, after a CNU is switched on, it may stay in anidle state until and unless an OLT assigns it a timeslot, during whichit can send data upstream to the OLT. To solve this problem, the EPoCMAC layer may need to implement an automatic discovery and registrationprocess for CNUs by the OLT. In an EPoC base system, services may belabeled as LLIDs. In order to implement end-to-end services, OLT and CNUmay need to establish LLID registration, where the OLT may assign aunique LLID to each CNU (or to each service within a CNU, in which casethe CNU may have multiple LLIDs) during the registration process.

In an EPON, the optical PHY may be relatively cleaner (e.g., less noisesignals) than the coax PHY of a coax network. Hence, EPON may not needto establish PHY channel communication before transmission. However,coax PHY may be noisier and need to perform channel training and/orestimation, such as frequency domain equalization (FEQ), ranging, andsounding, etc., before transmission. The coax PHY negotiation processmay be decoupled from the EPON MAC layer discovery and registration. Oneof the goals of this disclosure is to develop a point-to-multipoint coaxPHY auto negotiation mechanism, which may comprise coax PHY discoveryand parameters negotiations. This process may be independent from theEPON MAC, thus the OLT may have no knowledge of the CNU registrationprocess. After the coax PHY negotiation is complete, the EPoC MACregistration may start, and the OLT may discover newly connected CNUsand assign them LLIDs.

Disclosed herein are systems, apparatus, and methods for extending EPONMPCP to a non-optical portion of a hybrid access network, such as anEPoC or a DOCSIS network. Using an EPoC as an example, to establish acommunication channel between a CNU (coupled to a CLT via an electricalline) and an OLT (coupled to the CLT via an optical line), the CLT mayregister the CNU in itself first, and then facilitate registration ofthe CNU in the OLT. Various messages may be exchanged between the threeparties to perform registration, including for example, discoverymessages, register request messages, register messages, registeracknowledge messages, etc. PHY parameters and other tasks may also beperformed. After registering a CNU in an OLT, the OLT may assign a LLIDto the CNU. The CLT may snoop this process, that is, copying the LLIDand storing in a memory in the CLT.

Refer now to FIG. 1, which illustrates an embodiment of an EPoC network100 comprising an optical portion or segment 102 and an electricalsegment 104. The optical segment 102 may essentially be a PON and theelectrical segment 104 may be a coaxial cable network. The opticalsegment 102 may comprise an OLT 110 and one or more ONUs 128 coupled tothe OLT 110 via an optical distribution network (ODN). The ODN maycomprise an optical line or fiber 114 and an optical splitter 120 thatcouples the OLT 110 to an ONU 128. Similarly, the electrical segment 104may comprise one or more CLTs 130, each of which may be coupled to aplurality of CNUs 150 via an electrical distribution network (EDN). TheEDN may comprise coax cables 134, amplifiers 136 (only one shown as anexample), and cable taps or splitters 140 and 142.

In the EPoC network 100, each ONU 128 and its corresponding CLT 130 maybe fused together into a single box. The ONU-CLT box may act as a singledevice, which may reside at the curb or basement of a house or anapartment building. The ONU-CLT box may form an interface between theoptical and electrical segments 102 and 104. Following convention in theart, unless otherwise noted, hereinafter a box including an ONU 128 anda CLT 130 may simply be referred to as a CLT 130 that has ONUfunctionalities. It should be understood that the EPoC network 100 maycomprise any number of CLTs 130 and corresponding CNUs 150 for each OLT110. The components of the EPoC network 100 may be arranged as shown inFIG. 1 or any other suitable arrangement.

The optical segment 102 may be a communication network that does notrequire any active components to distribute data between the OLT 110 andthe CLTs 130. Instead, the optical segment 102 may use the passiveoptical components in the ODN to distribute data between the OLT 110 andthe CLT 130. The optical fiber 114 may have any suitable rating, such as1 or 10 Giga bits per second (Gbps). Examples of suitable protocols thatmay be implemented in the optical segment 102 to include asynchronoustransfer mode PON (APON) and the broadband PON (BPON) defined by the ITUTelecommunication Standardization Sector (ITU-T) G.983 standard, GigabitPON (GPON) defined by the ITU-T G.984 standard, the EPON defined by theIEEE 802.3ah standard, and the wavelength division multiplexing (WDM)PON (WDM-PON).

The OLT 110 may be any device configured to communicate with the CNUs150 via the CLT 130. The OLT 110 may reside in a local exchange, whichmay be a central office (CO). Further, the OLT 110 may couple or connectthe EPoC network 100 to another network 112, which may be any type ofnetwork such as the Internet, a synchronous optical network (SONET), oran asynchronous transfer mode (ATM) backbone. For example, the OLT 110may act as an intermediary between the CLTs 130 and the network 112.Specifically, the OLT 110 may forward data received from the network 112to the CLTs 130, and forward data received from the CLTs 130 onto thenetwork 112. Although the specific configuration of the OLT 110 may varydepending on the type of optical protocol implemented in the opticalsegment 102, in an embodiment, the OLT 110 may comprise an opticaltransmitter and an optical receiver. When the network 112 is using anetwork protocol that is different from the protocol used in the opticalsegment 102, the OLT 110 may comprise a converter that converts theprotocol of the network 112 to the protocol of the optical segment 102.The OLT converter may also convert the optical segment 102 protocol intothe network 112 protocol.

The ODN between the OLT 110 and the CLTs 130 may be a data distributionsystem that may comprise optical fiber cables, couplers, splitters,distributors, and/or other equipment. In data transmission, Ethernetpackets from the OLT 110 may pass through a 1×M passive splitter or acascade of splitters and reach each of the CLTs 130, where M may denotea number of CLTs in the EPoC network 100. M may have any suitable value,such as 4, 8, or 16, and may be decided by an operator depending onfactors like an optical power budget. Thus, packets may be broadcastedby the OLT 110 and selectively extracted by the CLTs 130. In anembodiment, the optical fiber cables, couplers, splitters, distributors,and/or other equipment are passive optical components. Specifically, theoptical fiber cables, couplers, splitters, distributors, and/or otherequipment may be components that do not require any power to distributedata signals between the OLT 110 and the CLTs 130. It should be notedthat, if needed, the optical fiber cables may be replaced by any opticaltransmission media. In some embodiments, the ODN may comprise one ormore passive or active optical amplifiers. The ODN may extend from theOLT 110 to the CLTs 130 including ONUs in a branching configuration asshown in FIG. 1, but may be alternatively configured as determined by aperson of ordinary skill in the art.

The CLTs 130 may be remotely coupled to the OLT 110. In someembodiments, one or more CLTs may be located within the OLT 110. In thedownstream direction, each CLT 130 may be any device or componentconfigured to receive downstream data from the OLT 110, process thedownstream data, and transmit the processed downstream data tocorresponding CNUs 150. The CLT 130 may convert the downstream dataappropriately to transfer the data between the optical segment 102 andthe electrical segment 104. Although terms “upstream” and “downstream”may be used throughout to denote the locations of various networkfeatures relative to the OLT or similar unit, those skilled in the artwill appreciate that the data flow on the network in the embodiments ofthe disclosure is bi-directional. Downstream data received by a CLT 130may be in the form of optical signals, and downstream data transmittedby a CLT 130 may be in the form of electrical signals that may have adifferent logical structure as compared with the optical signals. Insome embodiments, the CLT 130 is transparent to the CNUs 150 and the OLT110 in the sense that downstream data sent from the OLT 110 to the CNU150 may be directly addressed to the CNU 150 (e.g. using a LLID or adestination address), and vice-versa. As such, the CLT 130 intermediatesbetween network segments, namely an optical segment 102 and anelectrical segment 104 in the example of FIG. 1.

The electrical segment 104 of the EPoC network 100 may be similar to anyknown electrical communication system. For example, the electricalsegment 104 may also be a P2MP network. Downstream data from a CLT 130may pass through amplifier(s) and a tap or splitter or a cascade of tapsor splitters to reach one or more CNUs 150. In an embodiment, downstreamdata transmission from a CLT 130 to CNUs 150 may not be a broadcast;instead, a media access plan (MAP) may be used to allocate differentsub-carrier groups to different CNUs using orthogonal frequency-divisionmultiple access. Thus, in some cases, downstream transmissions may beunicast from the OLT 110 to the CNUs 150.

The electrical segment 104 may not require any active components todistribute data between the CLTs 130 and the CNUs 150. Instead, theelectrical segment 104 may use the passive electrical components in theelectrical segment 104 to distribute data between the CLTs 130 and theCNUs 150. Alternatively, the electrical segment 104 could use someactive components, such as amplifiers 136. Examples of suitableprotocols that may be implemented in the electrical segment 104 includeMoCA, G.hn, HPNA, and Home Plug A/V, etc. The EDN between the CLTs 130and the CNUs 150 may be a data distribution system that compriseselectrical cables (e.g. coaxial cable and twisted wires), couplers,splitters, distributors, and/or other equipment. In an embodiment, theelectrical cables, couplers, splitters, distributors, and/or otherequipment are passive electrical components. Specifically, theelectrical cables, couplers, splitters, distributors, and/or otherequipment may be components that do not require any power to distributedata signals between the CLT 130 and the CNU 150. It should be notedthat, if needed, the electrical cables may be replaced by any electricaltransmission media. In some embodiments, the EDN may comprise one ormore electrical amplifiers 136. The EDN may extend from each CLT 130 toits corresponding CNUs 150 in a branching configuration as shown in FIG.1, but may be alternatively configured as determined by a person ofordinary skill in the art.

In an embodiment, each CNU 150 may be any device configured tocommunicate with the OLT 110, the CLT 130, and any user devices 160.Specifically, the CNUs 150 may act as an intermediary between the OLT110 and the user devices 160. For example, each port of the OLT 110 mayserve 32, 64, 128, or 256 CNUs, and depending on the number of CNUspresent in the EPoC network 100, a suitable number (e.g., 4, 8, or 16)of CLTs 130 may be deployed per OLT port. An examplary distance betweenthe OLT 110 and a CLT 130 may be in the range of 10 to 20 kilometers,and an examplary distance between a CLT 130 and a CNU 150 may be in therange of 100 to 500 meters. Further, each CNU 130 may serve any suitablenumber (e.g., 3 or 4) of subscribers or user devices 160. For instance,the CNUs 150 may forward data received from the OLT 110 to the userdevices 160, and forward data received from the user devices 160 ontothe OLT 110.

Although the specific configuration of the CNUs 150 may vary dependingon the type of network 100, in an embodiment a CNU 150 may comprise anelectrical transmitter configured to send electrical signals to a CLT130 and an electrical receiver configured to receive electrical signalsfrom the CLT 130. Additionally, the CNU 150 may comprise a converterthat converts the electrical signal into electrical signals for the userdevices 160, such as signals in an ATM protocol, and a secondtransmitter and/or receiver that may send and/or receive the electricalsignals to the user devices 160. In some embodiments, CNUs 150 andcoaxial network terminals (CNTs) are similar, and thus the terms areused interchangeably herein. The CNUs 150 may typically be located atend-user locations, such as the customer premises, but may be located atother locations as well.

The user devices 160 may be any devices configured to interface with auser or subscriber. For example, the user devices 160 may includedesktop computers, laptop computers, tablets, mobile phones,smartphones, telephones, mobile telephones, residential gateways,televisions, set-top boxes, and so forth.

FIG. 2 illustrates an embodiment of a DOCSIS network 200, which may bestructurally similar to the EPoC network 100. The DOCSIS network 200 maycomprise a cable modem termination system (CMTS) 210, at least onehybrid fiber coax (HFC) node 230, any number of cable modems (CMs) 250and/or set-top box (STB) 252 arranged as shown in FIG. 2. Specifically,the HFC node 230 may be coupled to the CMTS 210 via an optical fiber214, and the CMs 250 and/or STB 252 may be coupled to the HFC node 230via electrical cables, one or more amplifiers (e.g., amplifiers 236 and238), and at least one splitter 240). In implementation, the CMTS 210may be considered equivalent or similar to the OLT 110 in FIG. 1, theHFC node 230 may be considered equivalent or similar to a CLT 130 inFIG. 1, and a CM 250 or a STB 252 may be considered equivalent orsimilar to a CNU 150 in FIG. 1. Note that the HFC node 230 may beremotely coupled to the CMTS 210, or sometimes reside in the CMTS 210.The CMTS 210 may sometimes be equipped with part or all of thefunctionalities of the HFC node 230. For example, methods and schemestaught herein (e.g., part of registration protocols) may be implementedby the CMTS 210 if desired. Instead of using a LLID, each CM 250, or STB252, or each service in a CM 250, or each service in a STB 252, may beidentifiable using a destination address (DA). The DA may be containedin a preamble of an Ethernet frame. A person of ordinary skill in theart will recognize similarities between the networks 100 and 200, andthat schemes and methods taught by this disclosure will be applicable tothe DOCSIS network 200 (adopting minor modifications). Accordingly, inthe interest of conciseness the DOCSIS network 200 will not be describedas detailed as the EPoC network 100.

Although not illustrated and discussed exhaustively, it should beunderstood that principles of this disclosure may be applicable to anyhybrid access network that employs an optical portion or segment. FIG. 3illustrates an embodiment of a hybrid access network 300, which may bestructurally similar to the EPoC network 100 or the DOCSIS network 200.The network 300 may comprise a CO equipment 310, one or more middleboxes330, and a plurality of CPEs 350 arranged as shown in FIG. 3.Specifically, the middleboxes 330 may be coupled to the CO equipment 310via an optical line comprising optical fibers 314 and at least onesplitter 320. The CPEs 350 may be coupled to a middlebox 330 viaelectrical lines comprising electrical cables and at least one splitter340. Note that a middlebox 330 may be remotely coupled to the COequipment 310, or sometimes reside in the CO equipment 310. A CPE 350may be a plug-and-play device from a user's perspective. Further, eachCPE 350 may be identifiable using a MAC layer identifier 453 (in shortas MAC ID) contained in a preamble of an Ethernet frame. This mayinclude some cases where each service in a CPE 350 is identifiable usinga MAC ID.

In implementation, the OLT 110 in FIG. 1 or the CMTS 210 in FIG. 2 maybe considered a specific case of the CO equipment 310, a CLT 130 or aHFC node 230 may be considered a specific case of the middlebox 330, anda CNU 150 or a CM 250 or a STB 252 may be considered a specific case ofthe CPE 350. Depending on the application or context, a middlebox 330may be referred to by various names, including but not limited to: CLT,HFC node, optical coax converter unit (OCU), coax media converter (CMC),media converter (MC), and fiber to coax unit (FCU). A person of ordinaryskill in the art will recognize similarities between the networks 100,200, and 300, and that schemes and methods taught for one specific typeof network will be applicable to a more general network, such as thehybrid access network 300 (adopting minor modifications as necessary).Accordingly, in the interest of clarity, in following descriptionsexamplary embodiments of apparatus, systems, schemes, and methods willmainly direct toward an EPoC network, with the understanding that thesame or similar principles may be applied to any general hybrid accessnetwork.

FIG. 4 illustrates an embodiment of part of a layer architecture 400 ina hybrid access network (e.g., in the hybrid access network 300). Asshown in FIG. 4, a CO equipment 310 may have a MAC layer 412 and a PHYlayer 414 underneath. A middlebox 330 may have a MAC layer 432, and twoPHY layers 434 and 436 underneath the MAC layer 432. A CPE 350 may havea MAC layer 452 and a PHY layer 454 underneath. The MAC layers 412, 432,and 452 may be similar to each other. For example, in an EPoC setting,the MAC layers 412, 432, and 452 may all be Ethernet MAC layersprocessing Ethernet frames. The middlebox 330 serves as an interfacepoint between an optical segment and an electrical segment of the hybridaccess, thus its PHY layer 434 may interact with the PHY layer 414,while its PHY layer 436 may interact with the PHY layer 454. In the EPoCsetting, the PHY layers 414 and 434 may be EPON optical PHY layers, andthe PHY layers 436 and 454 may be EPoC coax PHY layers.

The CO equipment 310 may have an identifier, and so may the CLT 330. AMAC layer identifier 453 (in short as MAC ID) may be used in the MAClayer 452, and a PHY layer identifier 455 (in short as PHY ID) may beused in the PHY layer 454. Both the MAC ID 453 and the PHY ID 455 may beused on different layers to identify the CPE 350. For example, the COequipment 310 may assign the MAC ID 453 to the CPE 350, and themiddlebox 330 may assign the PHY ID 455 to the CPE 350. Further, themiddlebox 330 may store a lookup or mapping table, which comprises boththe MAC ID 453 and the PHY ID 455 for multiple CPEs including the CPE350. In an EPoC network, the MAC ID 453 may be a LLID of a CNU, while ina DOCSIS network, the MAC ID 453 may be a DA of a CM or a STB.

The layer architecture 400 may be considered a convergence layerarchitecture. Depending on the implementation, there may be a variety oflayer architectures for a hybrid access network, including but notlimited to, convergence layer, repeater architecture, bridgedarchitecture, and any combination thereof. One with ordinary skill inthe art will recognize that schemes and methods disclosed herein may beemployed to any layer architectures.

FIG. 5 illustrates an embodiment of a registration protocol 500implemented in an EPoC network (e.g., the EPoC network 100). Theregistration protocol 500 may be a MPCP that allows a CNU 150 to beregistered in both the CLT 130 and the OLT 110. The registrationprotocol 500 may comprise any number of steps, e.g., 8 steps labeled as510, 520, 530, 540, 550, 560, 570, and 580 in FIG. 5. Steps 510 to 530may be considered a first stage 502 for registration of the CNU 150 inthe CLT 130, while steps 540 to 580 may be considered a second stage 504for registration of the CNU 150 in the CLT 130. Further, the stage 502may be implemented on a physical layer (in short as PHY) to completecoax PHY discovery and parameter negotiation, while the stage 504 may beimplemented on a media access control layer (in short as MAC) tocomplete EPoC MAC discovery and registration.

After the CNU 150 is powered on and connected to an electrical line(e.g., a coax cable in the EPoC network), the CNU 150 may beginlistening to the downstream coax channel. In step 510, the CLT 130 mayallocate a coax PHY discovery window or time period by transmitting orsending out a discovery message to all CNUs coupled to the CLT 130 viaelectrical lines. The discovery message may be broadcasted periodicallyfor discovering newly connected CNUs. The downstream coax channel maycomprise a control channel on reserved and spaced subcarriers or tones.The reserved tones may be selected from a frequency spectrum of thedownstream channel to carry a downstream media access plan (MAP). TheCNU 150 may be aware of the control channel. Specifically, by decodingthe downstream MAP in every orthogonal frequency-division multiplexing(OFDM) symbol, the CNU 150 may detect or sense when the CLT 130 isperforming step 510, that is, broadcasting discovery messages to allCNUs coupled to the CLT 130. The discovery message may comprise thedownstream MAP, which contains all LLIDs of CNUs already registered inthe OLT 110. Accordingly, CNUs already registered in the CLT 130 mayignore the discovery message, while the newly connected CNU 150 mayprocess and respond to the discovery message.

A discovery message may comprise various information useful forcommunication between the CLT 130 and the CNU 150. In an embodiment, thediscovery message may specify an upstream channel descriptor (UCD),which informs the CNU 150 which upstream frequencies to transmit on,symbol rate, modulation profile, and other parameters necessary forcommunication. In addition, the discovery message may comprise anupstream MAP, which may specify allocation of bandwidth to the CNU 150,that is, using which bandwidth the CNU 150 may respond to the CLT 130.

In step 520, the CNU 150 may transmit a register request message,denoted as REGISTER_REQ, to the CLT 130. The REGISTER_REQ may betransmitted and received on the PHY. In step 530, the CLT 130 mayrespond to the REGISTER_REQ with a register, denoted as REGISTER. Theregister message may be transmitted from the CLT 130 to the CNU 150 toindicate completion of registration. Alternatively, the CLT 130 maytransmit a register continue message to the CNU 150 to indicate thatfurther processes are needed before registration of the CNU 150 can becompleted. Various PHY parameters and/or processes may be negotiatedbetween the CLT 130 and the CNU 150 through the register request andresponse messages during steps 520 and 530. Examplary PHY parameters andprocesses include, but are not limited to, ranging, forward errorcorrection, sounding, FEQ, profile negotiation in terms of channelfrequencies, channel numbers, other parameters or processes, andcombinations thereof.

Since PHY parameter and process negotiations (e.g., ranging) maysometimes take multiple attempts, the steps 520 and 530 may need toiterate more than once. Once negotiation is completed, the CLT 130 mayassign a PHY ID to the CNU 150, and transmit a register messagecomprising the PHY ID to the CNU 150. The CLT 130 may also store the PHYID in its own memory. After receiving the PHY ID, the CNU 150 hasfinished PHY registration with the CLT 130. Depending on theimplementation, the CNU 150 may or may not send a register acknowledgemessage to the CLT 130 to confirm its registration. After registration,a coax channel between the CLT 130 and the CNU 150 may be initialized.Note that in stage 502, the CNU 150 may still lack a LLID it needs tocommunicate with the OLT 110.

In the stage 504, the CLT may facilitate the registration of the CNU 150in the OLT 110 by serving as an intermediary. Specifically, in step 540,the OLT may allocate an optics discovery window by transmitting a seconddiscovery message to the CLT 130 via an optical line. In implementation,the second discovery message may be broadcasted periodically (e.g., asmultiple messages having the same or similar contents) to all CLTscoupled to the OLT 110 via optical lines, including the CLT 130 shown inFIG. 5. The second discovery message may be broadcasted for the purposeof registering all newly connected CNUs in the OLT 110.

In step 550, the CLT 130 may transform the optics discovery window toanother coax discovery window for the CNU 150. Specifically, the CLT 130may convert the second discovery message into a converted discoverymessage, and then transmit the converted discovery message to the CNU150.

In step 560, the CLT 130 may relay a second register request message(i.e., REGISTER_REQ) from the CNU 150 to the OLT 110. Specifically, aMAC layer of the CNU 150 may transmit the second register requestmessage to the CLT 130, which may then forward or relay it to the OLT110. Note that relaying or forwarding a message herein may include casesin which certain processing are applied to the message prior torelaying. For example, to fit the second register request message forpropagation in an optical line between the OLT 110 and the CLT 130, theCLT 130 may convert a structure of the second register request messageas necessary. For another example, the CLT 130 may change a time stampcontained in a message to address potential time differences between thecoax network and the optical network.

In step 570, the OLT 110 may parse and verify the second registerrequest message. After verification, the OLT 110 may allocate or assigna LLID to the CNU 150 by transmitting a second register message (i.e.,REGISTER) comprising the LLID to the CNU 150 via the CLT 130, whichrelays the register message. The LLID may be unique for the CNU 150.Depending on the implementation, the CNU 150 may have one LLID or eachservice in the CNU 150 may have its own LLID. The CNU 150 may store itsassigned LLID(s) to indicate registration of itself in the OLT 110.

Further, the CLT 130 may snoop the process of CNU registration, that is,copy the LLID for the CNU 150 from the second register message, andstore the LLID to its own memory. Recall that the CLT 130 may alreadyhave the PHY ID for the CNU 150, thus the CLT 130 may establishcorrespondence between the PHY ID and the LLID for the CNU 150. Forexample, the CLT 130 may setup a mapping or lookup table to indicatecorrespondence from the PHY ID to the LLID, or vice versa. In addition,for request and allocation of bandwidth, GATE and REPORT messages may becommunicated between the OLT 110 and the CNU 150, and the CLT 130 mayrelay the messages.

In step 580, the CNU 150 may transmit a register acknowledge message,denoted as REGISTER_ACK, to the OLT 110 via the CLT 130. REGISTER_ACKmay signal that the registration of the CNU 150 in the OLT 130 has beensuccessful. Thus, a channel between the OLT 110 and the CNU 150 via theCLT 130 may be initialized, and data may be communicated. It can be seenthat a MPCP has been effectively extended from an EPON to an EPoC.

Table 1 illustrates an embodiment of a LLID lookup table, which may bestored in a buffer of the CLT 130. The LLID lookup table may comprisevarious information, such as PHY IDs of all CNUs coupled to the CLT 130,LLIDs of all CNUs coupled to the CLT 130, corresponding profiles foreach CNU, and channel parameters such as fast Fourier transform (FFT)sizes (4092 in Table 1). Note that in Table 1, each CNU may correspondto one LLID.

TABLE 1 an examplary LLID lookup table CNU ID LLID Profile MappingChannel Parameters CNU 1 = PHY ID X Null Profile A 4092 FFT CNU 2 = PHYID Y . . . . . . CNU N = PHY ID Z

Table 2 illustrates another embodiment of a LLID lookup table, which maybe stored in a buffer of the CLT 130. The LLID lookup table may comprisevarious information, such as PHY IDs of all CNUs coupled to the CLT 130,LLIDs of all CNUs coupled to the CLT 130, corresponding profiles foreach CNU, and channel parameters such as FFT sizes, cyclic prefixlength, etc. Note that in Table 2, each CNU corresponds to multipleLLIDs, each of which may correspond to one service. Further, a profile(e.g., profile A) may comprise a modulation order or coding schemeapplied to a specific CNU. Channel Parameters may contain OFDM channelinformation, such as symbol duration, FFT size, cyclic prefix (CP)length, and so on. Also, quality of service (QoS) may be based on eachLLID, and may be extended from the OLT 110, to the CLT 130, and furtherto CNUs. QoS may be extended by applying traffic shaping based on eachLLID to guarantee service provider's service level agreement (SLA).

TABLE 2 another examplary LLID lookup table QoS Profile Channel orTraffic CNU ID LLID Mapping Parameters Shaping CNU 1 = PHY ID X LLID1;Profile A FFT Size; CP Per LLID LLID2 Length, etc. based QoS CNU 2 = PHYID Y LLID3; . . . LID4 CNU N = PHY ID Z

By applying schemes disclosed herein, EPON MPCP signaling protocol maybe extended to support EPoC network through OLT and CNU registration.LLID lookup table in the CLT may comprise information designed to map tothe OFDM channel or profile information, so that the OLT can communicatewith the CNUs across optical and electrical lines. Note that EPON ONUsmay coexist with CNU in the EPoC architecture, where MPCP from OLT mayrun on either ONU connected to an EPON network, or a CNU connected to anEPoC network.

FIGS. 6A and 6B illustrate an embodiment of a registration method 600,which may be implemented by a middlebox (e.g., the middlebox 330) in ahybrid access network (e.g., the hybrid access network 300). The method600 may be executed by the middlebox to interact with a CO equipmentcoupled to the middlebox via an optical line and a plurality of CPEscoupled to the middlebox via electrical lines. As a result, one or morenewly connected CPEs may be registered in the middlebox and in the COequipment.

The method 600 may start with step 610, wherein the method 600 maytransmit a first discovery message to a plurality of CPEs including aCPE which needs to be registered. Recall that discovery messages may bebroadcasted periodically, thus the first discovery message may be any ofthe broadcasted messages. In step 620, the method 600 may receive afirst register request message (e.g., on the PHY layer) from the CPE,wherein the first register request message is generated by the CPE basedon the first discovery message. In step 630, the method 600 may assign aPHY ID to the CPE based on the first register request message. The PHYID may also be stored in the middlebox. In step 640, the method 600 maytransmit a first register message comprising the PHY ID to the CPE. Thefirst register message may be broadcasted to all CPEs, but otheralready-registered CPEs may ignore the message. In step 642, the method600 may further exchange messages between the CPE and the middlebox tonegotiate one or more physical layer parameters. Steps 610 to 640 or 642may enable the CPE to be registered in the middlebox.

Next, in step 650, the method 600 may receive a second discovery message(e.g., on the MAC layer) from the CO equipment. In step 660, the method600 may convert or transform the second discovery message to a converteddiscovery message that is suitable for transmission over electricallines. In step 670, the method 600 may transmit the converted discoverymessage to the plurality of CPEs, wherein the converted discoverymessage may or may not comprise a source (e.g., an ID for the COequipment and/or ID for the middlebox).

In step 680, the method 600 may relay a second register request message(e.g., on MAC layer) from the CPE to the CO equipment, wherein thesecond register request message is generated by the CPE based on thesecond discovery message. Recall that relaying a message may includesituations in which conversion or processing are performed by the method600, e.g., to enable the message to travel appropriately in a medium.For example, the middlebox may change a time stamp contained in amessage to address potential time differences between the coax networkand the optical network. In step 690, the method 600 may relay a secondregister message from the CO equipment to the CPE, wherein the secondregister message comprises a MAC ID for the CPE equipment. The MAC IDmay be assigned by and transmitted from the CO equipment. In step 692,the method 600 may store the PHY ID and the MAC ID to establish mappingbetween the two IDs. Storing of the MAC ID may occur during or afterrelaying the second register message. In step 694, the method 600 mayrelay a register acknowledge message from the CPE to the CO equipment,wherein the register acknowledge message is generated by the CPE inresponse to the second register message. Steps 650 to 694 may beexecuted by the middlebox to facilitate registration of the CPE in theCO equipment.

It should be understood by one with ordinary skill in the art thatmodification and variations may be applied to the method 600 within thescope of this disclosure. For example, storing PHY IDs may occur at anysuitable time, and mapping PHY IDs with MAC IDs may occur at any time,e.g., after all other steps are completed. In addition, mapping PHY IDswith MAC IDs may use any suitable data structure. Some steps may beskipped or changed in execution order if needed.

The schemes described above may be implemented on a network component,such as a computer or network component with sufficient processingpower, memory resources, and network throughput capability to handle thenecessary workload placed upon it. FIG. 7 is a schematic diagram of anembodiment of a network component or node 1500 suitable for implementingone or more embodiments of the systems and methods disclosed herein,such as the registration protocol 500 and the registration method 600.

The network node 1500 includes a processor 1502 that is in communicationwith memory devices including secondary storage 1504, read only memory(ROM) 1506, random access memory (RAM) 1508, input/output (I/O) devices1510, and transmitter/receiver 1512. Although illustrated as a singleprocessor, the processor 1502 is not so limited and may comprisemultiple processors. The processor 1502 may be implemented as one ormore central processor unit (CPU) chips, cores (e.g., a multi-coreprocessor), field-programmable gate arrays (FPGAs), application specificintegrated circuits (ASICs), and/or digital signal processors (DSPs),and/or may be part of one or more ASICs. The processor 1502 may beconfigured to implement any of the schemes described herein, includingthe registration protocol 500 and the registration method 600. Theprocessor 1502 may be implemented using hardware or a combination ofhardware and software.

The secondary storage 1504 is typically comprised of one or more diskdrives or tape drives and is used for non-volatile storage of data andas an over-flow data storage device if the RAM 1508 is not large enoughto hold all working data. The secondary storage 1504 may be used tostore programs that are loaded into the RAM 1508 when such programs areselected for execution. The ROM 1506 is used to store instructions andperhaps data that are read during program execution. The ROM 1506 is anon-volatile memory device that typically has a small memory capacityrelative to the larger memory capacity of the secondary storage 1504.The RAM 1508 is used to store volatile data and perhaps to storeinstructions. Access to both the ROM 1506 and the RAM 1508 is typicallyfaster than to the secondary storage 1504.

The transmitter/receiver 1512 may serve as an output and/or input deviceof the network node 1500. For example, if the transmitter/receiver 1512is acting as a transmitter, it may transmit data out of the network node1500. If the transmitter/receiver 1512 is acting as a receiver, it mayreceive data into the network node 1500. Further, thetransmitter/receiver 1512 may include one or more optical transmitters,one or more optical receivers, one or more electrical transmitters,and/or one or more electrical receivers. The transmitter/receiver 1512may take the form of modems, modem banks, Ethernet cards, universalserial bus (USB) interface cards, serial interfaces, token ring cards,fiber distributed data interface (FDDI) cards, and/or other well-knownnetwork devices. The transmitter/receiver 1512 may enable the processor1502 to communicate with an Internet or one or more intranets. The I/Odevices 1510 may be optional or may be detachable from the rest of thenetwork node 1500. The I/O devices 1510 may include a video monitor,liquid crystal display (LCD), touch screen display, or other type ofdisplay. The I/O devices 1510 may also include one or more keyboards,mice, or track balls, or other well-known input devices.

It is understood that by programming and/or loading executableinstructions onto the network node 1500, at least one of the processor1502, the secondary storage 1504, the RAM 1508, and the ROM 1506 arechanged, transforming the network node 1500 in part into a particularmachine or apparatus (e.g., a CO equipment, a middlebox, or a CPE havingthe functionality taught by the present disclosure). The executableinstructions may be stored on the secondary storage 1504, the ROM 1506,and/or the RAM 1508 and loaded into the processor 1502 for execution. Itis fundamental to the electrical engineering and software engineeringarts that functionality that can be implemented by loading executablesoftware into a computer can be converted to a hardware implementationby well-known design rules. Decisions between implementing a concept insoftware versus hardware typically hinge on considerations of stabilityof the design and numbers of units to be produced rather than any issuesinvolved in translating from the software domain to the hardware domain.Generally, a design that is still subject to frequent change may bepreferred to be implemented in software, because re-spinning a hardwareimplementation is more expensive than re-spinning a software design.Generally, a design that is stable that will be produced in large volumemay be preferred to be implemented in hardware, for example in an ASIC,because for large production runs the hardware implementation may beless expensive than the software implementation. Often a design may bedeveloped and tested in a software form and later transformed, bywell-known design rules, to an equivalent hardware implementation in anapplication specific integrated circuit that hardwires the instructionsof the software. In the same manner, as a machine controlled by a newASIC is a particular machine or apparatus, likewise a computer that hasbeen programmed and/or loaded with executable instructions may be viewedas a particular machine or apparatus.

At least one embodiment is disclosed and variations, combinations,and/or modifications of the embodiment(s) and/or features of theembodiment(s) made by a person having ordinary skill in the art arewithin the scope of the disclosure. Alternative embodiments that resultfrom combining, integrating, and/or omitting features of theembodiment(s) are also within the scope of the disclosure. Wherenumerical ranges or limitations are expressly stated, such expressranges or limitations may be understood to include iterative ranges orlimitations of like magnitude falling within the expressly stated rangesor limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.;greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example,whenever a numerical range with a lower limit, R₁, and an upper limit,R_(u), is disclosed, any number falling within the range is specificallydisclosed. In particular, the following numbers within the range arespecifically disclosed: R=R₁+k*(R_(u)−R₁), wherein k is a variableranging from 1 percent to 100 percent with a 1 percent increment, i.e.,k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . , 50percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97percent, 98 percent, 99 percent, or 100 percent. Moreover, any numericalrange defined by two R numbers as defined in the above is alsospecifically disclosed. The use of the term “about” means +/−10% of thesubsequent number, unless otherwise stated. Use of the term “optionally”with respect to any element of a claim means that the element isrequired, or alternatively, the element is not required, bothalternatives being within the scope of the claim. Use of broader termssuch as comprises, includes, and having may be understood to providesupport for narrower terms such as consisting of, consisting essentiallyof, and comprised substantially of Accordingly, the scope of protectionis not limited by the description set out above but is defined by theclaims that follow, that scope including all equivalents of the subjectmatter of the claims. Each and every claim is incorporated as furtherdisclosure into the specification and the claims are embodiment(s) ofthe present disclosure. The discussion of a reference in the disclosureis not an admission that it is prior art, especially any reference thathas a publication date after the priority date of this application. Thedisclosure of all patents, patent applications, and publications citedin the disclosure are hereby incorporated by reference, to the extentthat they provide exemplary, procedural, or other details supplementaryto the disclosure.

While several embodiments have been provided in the present disclosure,it may be understood that the disclosed systems and methods might beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and may be made without departing from the spirit and scopedisclosed herein.

What is claimed is:
 1. An apparatus comprising: a processor configuredto: generate a gate message based on a registration of an endpoint at amiddlebox; and process a register acknowledgement message based on thegate message; a transmitter coupled to the processor and configured totransmit the gate message; and a receiver coupled to the processor andconfigured to receive the register acknowledgement message.
 2. Theapparatus of claim 1, wherein the apparatus is an optical line terminal(OLT).
 3. The apparatus of claim 1, wherein the apparatus is one of acable modem termination system (CMTS) or a central office (CO).
 4. Theapparatus of claim 1, wherein the endpoint is a coaxial network unit(CNU) and the middlebox is a fiber coaxial unit (FCU).
 5. The apparatusof claim 1, wherein the transmitter is further configured to transmitthe gate message to a fiber coaxial unit (FCU) and towards a coaxialnetwork unit (CNU).
 6. The apparatus of claim 1, wherein the receiver isfurther configured to receive the register acknowledgement message froma fiber coaxial unit (FCU), wherein the register acknowledgement messageoriginated from a coaxial network unit (CNU).
 7. A method implemented inan apparatus, the method comprising: generating a gate message based ona registration of an endpoint at a middlebox; transmitting the gatemessage; receiving a register acknowledgement message based on the gatemessage; and processing the register acknowledgement message.
 8. Theapparatus of claim 7, wherein the apparatus is an optical line terminal(OLT).
 9. The apparatus of claim 7, wherein the apparatus is one of acable modem termination system (CMTS) or a central office (CO).
 10. Theapparatus of claim 7, wherein the endpoint is a coaxial network unit(CNU) and the middlebox is a fiber coaxial unit (FCU).
 11. The apparatusof claim 7, further comprising further transmitting the gate message toa fiber coaxial unit (FCU) and towards a coaxial network unit (CNU). 12.The apparatus of claim 7, further comprising further receiving theregister acknowledgement message from a fiber coaxial unit (FCU),wherein the register acknowledgement message originated from a coaxialnetwork unit (CNU).